The present invention relates to a method and apparatus for providing transport for a control signal. More particularly, the present invention relates to transporting via a first protocol a control signal of a second protocol to a gateway to a network that utilizes that second protocol.
As communication needs have increased, various network architectures have been proposed to afford users with ever-increasing flexibility in conducting exchanges of information. One such architecture involves providing wireless communications services to enable a user to have mobile access to a communication network.
An example of a known mobile wireless communication architecture is shown in FIG. 8. In this configuration a wireless communication device, 800, can be used to establish communications with, for example, wireline telephone 804 via a wireless communication channel, represented by arrow 802. The channel is typically a radio frequency link controlled by a base station, e.g., 801, responsible for the geographic area or cell in which the device 800 is in use. The base station is under the control of a mobile switching center (MSC), 805, which controls switching of communications between base stations and a public telephone switched network (PSFN) 806. If a call is originated at telephone 804 destined for mobile communication device and the PSTN routes the call to the G-MSC (the Home MSC for this particular MIN:800). The G-MSC sends a control signal to signal transfer point (STP) 807 and that control signal is forwarded to a home location register (HLR) 808 associated with the mobile device 800 that is the intended recipient of the call. The HLR 808 responds with information regarding which MSC the mobile device 800 is currently registered in. The G-MSC then routes the call to the appropriate S-MSC 805 which in turn initiates radio contact through base station 801 with the mobile device.
Over time it has become desirable to incorporate wireless capabilities in an office environment. In this manner, a party associated with a given office and having, for example, a given extension number as in a private branch exchange (PBX) arrangement can have a mobile wireless device and be contactable even when away from a wireline phone associated with the PBX extension number.
The ATand T Wireless Services (AWS) Wireless Office Service (WOS) is a service product that provides in-building and on-campus wireless services in conjunction with a customer""s existing communications system (e.g., PBX). The service allows customers to use their internal 4-digit PBX dial plan on their wireless phones and allows them to receive on their wireless phones calls originally made to their PBX phone. These features are available whether the user is in-building, on-campus or roaming away from these areas nationally or even internationally.
Originally, WOS was provided via MSC features, functionality and RF coverage of a macro cellular network. An example of one WOS arrangement that has been proposed is illustrated in FIG. 1. Equipment 101 resides on a customer""s premises. It includes a traditional PBX 102 and wireline phones 103, 104 connected to the PBX and each having an extension number associated therewith. If a call is directed to one of the extension numbers, the PBX, can send the call to MSC 106 via PSTN 105 in an attempt to complete a wireless communication to device 110. The MSC 106 can be coupled to a base station 108 that provides coverage for the customer""s premises. This could be a base station positioned either on or off the customer""s premises. Where RF coverage was adequate, existing macro cells provided in-building and campus coverage. In other instances, new macro cells were deployed or micro cells were installed on the customer premises.
Wireless office systems currently under development aim to exploit the cost and technology curves of commodity computing platforms and consumer-product-like base stations in order to use Customer Premises Equipment (CPE), rather than traditional network infrastructure equipment, to provide the service. Lower equipment costs and the use of CPE are expected to increase the number of vendor and feature options available to customers and to stimulate demand for the service. Additionally, new functionality associated with automating certain RF engineering procedures is expected to lower deployment and operations costs typically borne by the network service provider.
In these newer wireless office systems, the equipment at the customer""s location looks and behaves like an MSC/visited Location Register (VLR) combination to the rest of the cellular network. Therefore, they support the IS-41 MAP. At present, IS-41 specifications allow data transfer services using SS7 or X.25. One option would be to treat each wireless office as an endpoint for the signaling network. For example, each such customer premises office could be an SS7 network endpoint with a direct connection into the signaling network.
If growth expectations are met, then the number of signaling endpoints in the network could increase substantially. A preliminary estimate indicates substantial outlays would be required to support wireless office systems customer premises equipment directly on the SS7 signaling network. Considerations other than cost also provide disincentives to terminating the signaling network directly at the customer""s premises. These include:
a) access by unauthorized people to SS7 links resulting in potential harm to the signaling network;
b) lack of control over access to facilities by authorized people;
c) reliability of CPE;
d) low link utilization for these wireless office systems (the link to the signaling network would be significantly under-utilized by a single customer premises office system); and
e) difficulty for vendors to shoulder development or procurement costs of full signaling network functionality.
Given these disadvantages it would be beneficial if there was another approach available to provide signaling network connectivity to the customer""s premises.
The present invention provides a signal transport mechanism that facilitates communication to a signaling network via existing communication facilities. In accordance with an embodiment of the present invention, a communication device at a customer premises generates a control signal in accordance with a first protocol. The generated control signal is wrapped into a transport mechanism in accordance with a second protocol and transmitted to a gateway. The gateway receives the signal of the second protocol, unwraps the generated control signal and forwards it to a signaling network which is operating with the first protocol. Likewise, the gateway wraps signaling network communications of the first protocol in a package consistent with the second protocol and then provides that package to the communications device for subsequent unwrapping.
In a more specific embodiment, the customer premises communication device includes a controller that emulates a mobile switching center and generates control signals consistent with IS-41 MAP (Mobile Application Part) protocols or GSM MAP protocols and the SS7 standards. The controller wraps an IS-41 message into a signal that comports with TCP/IP and transmits the packaged message over a wide area network to a gateway. At the gateway, the received, IS-41/GSM message is unwrapped and provided to the SS7 signaling network. In turn, the gateway can take SS7 network responses, package them in accordance with TCP/IP requirements and forward the responses to the customer premises communication device.
In accordance with the present invention, the customer premises communications device gains access to an SS7 network without requiring a dedicated connection. Furthermore, a gateway can service multiple customer premises communications devices thereby, enhancing link utilization and sharing the cost of SS7 access over a number of wireless office systems.